Distillation is one of the main methods to generate potable water from sea water. The main concept of distillation is sea water is heated to evaporate the water and then the water vapor is cooled to condense to produce fresh water. Since boiling temperatures of other contaminant such as salt, metals are very high, they will not be incorporated in the water vapor and will be left in the remaining solution. The fresh water is collected and piped to a container for usage. The remaining waste brine sea water is periodically refreshed.
Many variations of desalination process exist. For example, multi stage flash desalination reuses the energy into the water vapor to heat incoming sea water; therefore saving cost and energy in the process. However, this system is quite expensive and difficult to scale into smaller units. Vacuum desalination employs low pressure to enhance evaporation rate. This will also increase rate of desalination at the expense of energy needed to pump the chamber. Reverse osmosis desalination employs very high pressure of several hundred psi through a membrane to remove salt from the water. This system is scalable and likely more energy efficient than heat-based desalination; however, the system needs complex maintenance such as membrane changes and also vessels that can withstand such as high pressure.
In emergency desalination systems, such as that used in life rafts and survival kits, a very difference requirement exists. For example, a system that requires a significant heat source such as flash desalination may not be practical as emergency fuel sources quickly run out. Bulky and heavy Reverse Osmosis is also not practical as it is too heavy to carry around and will require significant electricity which is usually not available in emergency situations. A person needs a minimum of around 500 ml to 1 liter of water to survive a day. Any emergency desalination system has to provide close to that amount per day. Some solar desalination systems can provide that amount in ideal situation, but to provide consistent and sufficient water, especially for multiple survivors is indeed difficult.
Therefore, there is a need to invent a desalination system that is energy efficient, low cost, has higher conversion rate of vapor to water, and is scalable from a very large system to a portable system used in emergency.